1. Field of the Invention
The present invention relates generally to the identification of a specific portion of a given article with an identifying mark. More particularly, the invention relates to a method and means for the application of a color mark or label to a specific portion of an article, such as to the hot face of a kiln brick or liner, as such article is being conveyed along an assembly line.
2. Description of the Prior Art
In the manufacture of refractory liners, hereinafter designated as bricks, for use in lining kilns, furnaces and related apparatus, it is important that the specific portion or face of each brick ultimately exposed to the interior of the kiln, commonly known in the art as the "hot face", be readily apparent to the workman to facilitate the proper positioning of the brick in the kiln lining. Such bricks are normally provided with two tapered faces so that the overall configuration is somewhat wedge-shaped. However, since the taper is small compared with the overall dimensions of the brick, the hot face is not readily distinguishable from the opposite or cold face. Since kilns and furnaces are of a generally cylindrical configuration, a full lining therein requires that a plurality of circular rows of the bricks be placed against the interior surface thereof. The wedge-shaped configuration of each brick permits each such row of bricks to assume the required circular or ring configuration. If the bricks are correctly set in place within the furnace, the portions of the bricks exposed to the interior of the furnace will be the hot faces. Thus, by utilizing a hot face designation for each brick, it is assured that the bricks will be correctly set in place according to their wedge-shapes to form the circular furnace lining.
While the correct lining of any furnace is important for its proper operation and longevity, it is of even greater importance in the case of rotary furnaces or kilns because such furnaces are normally horizontal or inclined during use and their rotational motions tend to impart greater stresses to the furnace liner than would be experienced in the static or vertically oriented furnaces. Accordingly, if one refractory liner or brick is improperly set in place in a rotary kiln, an entire ring or circular layer of bricks could fail once rotation of the kiln commences.
Therefore, in order to assure the kiln liners or bricks are properly set in place within a furnace according to their wedge-shaped configuration, it is critical that the portions of the bricks which face the interior of the furnace and known as the hot faces be unmistakeably, marked, coded or designated as such during the manufacturing of the bricks. It has been proposed that the hot face portion of a kiln brick be so designated by painting the hot face portion a given color to not only indicate the hot face, but also to designate the specific type of brick by refractory composition. Accordingly, different colors can be utilized for the several varieties of refractory compositions, i.e. yellow for fired dolomite bricks, orange for tempered or resin-bonded dolomite bricks and green for 90% or higher concentration of burned or impregnated magnesite bricks.
Since kiln liners or bricks are normally manufactured at a relatively high production rate while utilizing both mechanical and manual manipulations and procedures, there is always a possibility of production errors. The known prior art techniques for accomplishing these procedures have been primarily based upon application of paint to the face thought to be the hot face and visually inspecting the painted bricks for errors, flaws or rejects. Such known prior art methods and procedures are time consuming and uneconomical. Because of the considerable amount of reliance placed upon human consistency, it is apparent that these known methods are not without the possibility of errors and omissions.